mysql中整数数据类型tinyint详解
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2022-06-18 16:32:06
目录1.1 tinyint类型说明1.2 实践环境说明1.3 加unsigned属性1.3.1 sql模式开启严格模式1.3.2 sql模式未开启严格模式1.4 加zerofill属性1.4.1 sq...
1.1 tinyint类型说明
数据类型 | 显示长度 | 占用字节 | 有符号 | 无符号 |
---|---|---|---|---|
tinyint | 加上unsigned/zerofill:3 不加unsigned/zerofill:4 |
1(8bit) | -128至127 | 0至255 |
#### 格式 id tinyint(m) [unsigned] [zerofill] 字段名 数据类型(显示长度,不指定指定) 无符号 无符号且前导零填充 #### 关于tinyint最大数值是怎样得来的 tinyint占用1字节,1字节占用8位,经过换算(2的8次方减1)就是255; #### 关于加上unsigned后的说明 加上unsigned属性后就是无符号(范围是0~255的整数,因为是整数,不会有符号"-",所以就是无符号) #### 关于加上zerofill后的说明 zerofill属性会把unsigned属性也给带上,这样就是无符号(范围是0~255,显示长度就是3),同时还会 进行前导零填充(没有达到显示长度的数值,例如:你插入1,显示的是001)。 #### 不加unsigned和zerofill的说明 字段后面不加上这两个属性中的任何一个,就表示是有符号(范围是-128~127,因为有符号"-",所有是有符号)。
1.2 实践环境说明
#### 数据库版本和默认的存储引擎 mysql> select @@version,@@default_storage_engine; +------------+--------------------------+ | @@version | @@default_storage_engine | +------------+--------------------------+ | 5.7.28-log | innodb | +------------+--------------------------+ 1 row in set (0.00 sec) #### 创建chenliang库 mysql> create database if not exists chenliang; query ok, 1 row affected (0.03 sec) mysql> show databases like "chenliang"; +----------------------+ | database (chenliang) | +----------------------+ | chenliang | +----------------------+ 1 row in set (0.03 sec) #### 进入chenliang库,并查看是否成功进入到库下面 mysql> use chenliang; database changed mysql> select database(); +------------+ | database() | +------------+ | chenliang | +------------+ 1 row in set (0.01 sec) #### 查看事务是否自动提交 mysql> select @@global.autocommit; +---------------------+ | @@global.autocommit | +---------------------+ | 1 | +---------------------+ 1 row in set (0.00 sec)
1.3 加unsigned属性
1.3.1 sql模式开启严格模式
sql_mode中开启了严格模式,即sql_mode参数中包含strict_trans_tables参数
#### 设置会话模式下的sql_mode中包含strict_trans_tables mysql> set session sql_mode="strict_trans_tables,no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution"; query ok, 0 rows affected (0.00 sec) mysql> select @@sql_mode\g *************************** 1. row *************************** @@sql_mode: strict_trans_tables,no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution 1 row in set (0.00 sec) #### 创建test1测试表(这里指定了unsigned,也就是无符号) mysql> create table if not exists test1( -> id tinyint unsigned -> )engine=innodb character set utf8 collate utf8_general_ci; query ok, 0 rows affected (0.06 sec) ## id字段类型是tinyint unsigned,范围就是0~255,其长度是3;因为255的长度是3; #### 查看test1表的表结构 mysql> desc test1; +-------+---------------------+------+-----+---------+-------+ | field | type | null | key | default | extra | +-------+---------------------+------+-----+---------+-------+ | id | tinyint(3) unsigned | yes | | null | | +-------+---------------------+------+-----+---------+-------+ 1 row in set (0.03 sec) #### 测试插入范围0~255范围整数和不在该范围内的整数 mysql> insert into test1 values(-1); # 插入数值-1,错误(不在0~255范围内) error 1264 (22003): out of range value for column 'id' at row 1 mysql> insert into test1 values(0); # 插入数值0,正常(在0~255范围内) query ok, 1 row affected (0.06 sec) mysql> insert into test1 values(255); # 插入数值255,正常(在0~255范围内) query ok, 1 row affected (0.05 sec) mysql> insert into test1 values(256); # 插入数值256,错误(不在0~255范围内) error 1264 (22003): out of range value for column 'id' at row 1 mysql> select * from test1; +------+ | id | +------+ | 0 | | 255 | +------+ 2 rows in set (0.00 sec)
1.3.2 sql模式未开启严格模式
sql_mode未开启严格模式,即sql_mode参数中不包含strict_trans_tables参数
#### 设置会话模式下sql_mode中不包含strit_trans_tables变量 mysql> set session sql_mode="no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution"; query ok, 0 rows affected, 1 warning (0.00 sec) mysql> select @@sql_mode\g *************************** 1. row *************************** @@sql_mode: no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution 1 row in set (0.00 sec) #### 创建test11表(这里指定了unsigned,也就是无符号) mysql> create table if not exists test11( -> id tinyint unsigned -> )engine=innodb character set utf8 collate utf8_general_ci; query ok, 0 rows affected (0.00 sec) ## id字段类型是tinyint unsigned,范围就是0~255,其长度是3;因为255的长度是3; #### 查看test11表的表结构 mysql> desc test11; +-------+---------------------+------+-----+---------+-------+ | field | type | null | key | default | extra | +-------+---------------------+------+-----+---------+-------+ | id | tinyint(3) unsigned | yes | | null | | +-------+---------------------+------+-----+---------+-------+ 1 row in set (0.00 sec) #### 测试插入范围0~255范围整数和不在该范围内的整数 mysql> insert into test11(id) values(-1); query ok, 1 row affected, 1 warning (0.00 sec) ## 不在范围内,插入没有报错(因为sql_mode中没有开启严格模式) ## 插入到表中的数据不是-1,而是0 mysql> insert into test11(id) values(0); query ok, 1 row affected (0.01 sec) ## 没报错,因为在范围内,插入到表中的也是0 mysql> insert into test11(id) values(255); query ok, 1 row affected (0.01 sec) ## 没报错,因为在范围内,插入到表中的也是255 mysql> insert into test11(id) values(256); query ok, 1 row affected, 1 warning (0.00 sec) ## 不在范围内,插入没有报错(因为sql_mode中没有开启严格模式) ## 插入到表中的数据不是256,而是255 mysql> select * from test11; +------+ | id | +------+ | 0 | | 0 | | 255 | | 255 | +------+ 4 rows in set (0.00 sec)
1.4 加zerofill属性
1.4.1 sql模式开启严格模式
sql_mode中开启了严格模式,即sql_mode参数中包含strict_trans_tables参数
## 设置会话模式下的sql_mode中包含strict_trans_tables mysql> set session sql_mode="strict_trans_tables,no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution"; query ok, 0 rows affected (0.00 sec) mysql> select @@sql_mode\g *************************** 1. row *************************** @@sql_mode: strict_trans_tables,no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution 1 row in set (0.00 sec) ## 创建test2测试表(这里指定了zerofill,会前导零填充,同时还会带上unsigned) mysql> create table if not exists test2( -> id tinyint zerofill -> )engine=innodb character set utf8 collate utf8_general_ci; query ok, 0 rows affected (0.01 sec) ## id字段类型是tinyint zerofill,范围就是0~255,其长度是3;因为255的长度是3; ## 查看test2表的表结构 mysql> desc test2; +-------+------------------------------+------+-----+---------+-------+ | field | type | null | key | default | extra | +-------+------------------------------+------+-----+---------+-------+ | id | tinyint(3) unsigned zerofill | yes | | null | | +-------+------------------------------+------+-----+---------+-------+ 1 row in set (0.00 sec) ## 测试插入范围0~255范围整数和不在该范围内的整数 mysql> insert into test2 values(-1); # 插入数值-1,错误(不在0~255范围内) error 1264 (22003): out of range value for column 'id' at row 1 mysql> insert into test2 values(0); # 插入数值0,正常(在0~255范围内) query ok, 1 row affected (0.06 sec) mysql> insert into test2 values(255); # 插入数值255,正常(在0~255范围内) query ok, 1 row affected (0.05 sec) mysql> insert into test2 values(256); # 插入数值256,错误(不在0~255范围内) error 1264 (22003): out of range value for column 'id' at row 1 mysql> select * from test2; +------+ | id | +------+ | 000 | | 255 | +------+ 2 rows in set (0.00 sec)
1.4.2 sql模式未开启严格模式
sql_mode未开启严格模式,即sql_mode参数中不包含strict_trans_tables参数
## 设置会话模式下sql_mode中不包含strit_trans_tables变量 mysql> set session sql_mode="no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution"; query ok, 0 rows affected, 1 warning (0.00 sec) mysql> select @@sql_mode\g *************************** 1. row *************************** @@sql_mode: no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution 1 row in set (0.00 sec) ## 创建test22表(这里指定了zerofill,会前导零填充,同时还会带上unsigned) mysql> create table if not exists test22( -> id tinyint zerofill -> )engine=innodb character set utf8 collate utf8_general_ci; query ok, 0 rows affected (0.00 sec) ## id字段类型是tinyint unsigned,范围就是0~255,其长度是3;因为255的长度是3; ## 查看test22表的表结构 mysql> desc test22; +-------+------------------------------+------+-----+---------+-------+ | field | type | null | key | default | extra | +-------+------------------------------+------+-----+---------+-------+ | id | tinyint(3) unsigned zerofill | yes | | null | | +-------+------------------------------+------+-----+---------+-------+ 1 row in set (0.00 sec) ## 测试插入范围0~255范围整数和不在该范围内的整数 mysql> insert into test22(id) values(-1); query ok, 1 row affected, 1 warning (0.00 sec) ## 不在范围,插入没报错(因为sql_mode中没有开启严格模式); ## 但到表中的不是-1,而是0,但因为有zerofill参数,所以显示时会前导零序填充; mysql> insert into test22(id) values(0); query ok, 1 row affected (0.01 sec) ## 没报错,因为在范围内,插入到表中的也是0 mysql> insert into test22(id) values(255); query ok, 1 row affected (0.01 sec) ## 没报错,因为在范围内,插入到表中的也是255 mysql> insert into test22(id) values(256); query ok, 1 row affected, 1 warning (0.00 sec) ## 不在范围,插入没报错(sql_mode中没有开启严格模式) ## 但到表中的数据不是256,而是255 mysql> select * from test22; +------+ | id | +------+ | 000 | | 000 | | 255 | | 255 | +------+ 4 rows in set (0.00 sec)
1.5 不加unsigned和zerofill属性
1.5.1 sql模式开启严格模式
sql_mode中开启了严格模式,即sql_mode参数中包含strict_trans_tables参数
## 设置会话模式下的sql_mode中包含strict_trans_tables mysql> set session sql_mode="strict_trans_tables,no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution"; query ok, 0 rows affected (0.00 sec) mysql> select @@sql_mode\g *************************** 1. row *************************** @@sql_mode: strict_trans_tables,no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution 1 row in set (0.00 sec) ## 创建test3表(不加unsigned和zerofill) mysql> create table test3( -> id tinyint -> )engine=innodb character set utf8 collate utf8_general_ci; query ok, 0 rows affected (0.06 sec) ## id字段的类型为tinyint,其范围是-128至127,其显示长度是4,因为要显示符号("-") ## 查看test3表的表结构 mysql> desc test3; +-------+------------+------+-----+---------+-------+ | field | type | null | key | default | extra | +-------+------------+------+-----+---------+-------+ | id | tinyint(4) | yes | | null | | +-------+------------+------+-----+---------+-------+ 1 row in set (0.01 sec) ## 测试插入-128~127范围的整数和不在该范围内的整数 mysql> insert into test3(id) values(-129); # 插入数值-129,错误,不在范围内 error 1264 (22003): out of range value for column 'id' at row 1 mysql> insert into test3(id) values(-128); # 插入数值-128,正确,在范围内 query ok, 1 row affected (0.00 sec) mysql> insert into test3(id) values(127); # 插入数值127,正确,在范围内 query ok, 1 row affected (0.01 sec) mysql> insert into test3(id) values(128); # 插入数值128,错误,不在范围内 error 1264 (22003): out of range value for column 'id' at row 1 mysql> select * from test3; +------+ | id | +------+ | -128 | | 127 | +------+ 2 rows in set (0.00 sec)
1.5.2 sql模式未开启严格模式
sql_mode中未开启严格模式,即sql_mode参数中不包含strict_trans_tables参数
## 设置会话模式下sql_mode中不包含strit_trans_tables变量 mysql> set session sql_mode="no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution"; query ok, 0 rows affected, 1 warning (0.00 sec) mysql> select @@sql_mode\g *************************** 1. row *************************** @@sql_mode: no_zero_in_date,no_zero_date,error_for_division_by_zero,no_auto_create_user,no_engine_substitution 1 row in set (0.00 sec) ## 创建test33表(不加unsigned和zerofill) mysql> create table test33( -> id tinyint -> )engine=innodb character set utf8 collate utf8_general_ci; query ok, 0 rows affected (0.00 sec) ## id字段的类型为tinyint,其范围是-128至127,其显示长度是4,因为要显示符号("-") ## 查看test33表的表结构 mysql> desc test33; +-------+------------+------+-----+---------+-------+ | field | type | null | key | default | extra | +-------+------------+------+-----+---------+-------+ | id | tinyint(4) | yes | | null | | +-------+------------+------+-----+---------+-------+ 1 row in set (0.00 sec) ## 测试插入-128~127范围的整数和不在该范围内的整数 mysql> insert into test33(id) values(-129); query ok, 1 row affected, 1 warning (0.00 sec) ## 不在范围内,插入未报错,因为sql_mode中没有开启严格模式 ## 插入到表中的不是-129,而是-128; mysql> insert into test33(id) values(-128); query ok, 1 row affected (0.01 sec) ## 在范围内,插入不报错,插入的是多少就是多少 mysql> insert into test33(id) values(127); query ok, 1 row affected (0.00 sec) ## 在范围内,插入不报错,插入的是多少就是多少 mysql> insert into test33(id) values(128); query ok, 1 row affected, 1 warning (0.01 sec) ## 不在范围内,插入未报错,因为sql_mode中没有开启严格模式 ## 插入到表中的不是128,而是127; mysql> select * from test33; +------+ | id | +------+ | -128 | | -128 | | 127 | | 127 | +------+ 4 rows in set (0.00 sec)
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